JPS63283037A - Statically attracting apparatus - Google Patents

Abstract

PURPOSE:To improve the lifetime of a statically attracting apparatus, by using a thin ceramic plate having an extremely high surface strength of sintered alumina for example, for forming the substrate attracting and holding surface of the apparatus which is directly contacted with a wafer to be treated. CONSTITUTION:An elastic insulating film 3 is deposited all over the surface of a base plate 1. First and second film-type electrodes 5A and 5B are adhered on the insulating film 3. A thin plate 6 of ceramics having an extremely high surface strength, of sintered alumina for example, is deposited on the insulating film 3 including the electrodes 5A and 5B, for providing a surface to be contacted with a wafer to be attracted 11. A series voltage is applied between the electrodes 5A and 5B from a series power supply 9. Since the thin plate 6 has a high surface resistance against friction, pressing or the like, the surface for attracting the wafer 11 will not be damaged mechanically. Further, since the insulating film 3 is elastic, any stress caused by thermal expansion between the thin plate 6 and the base plate 1 is absorbed by the elasticity of the insulating film 3. Thus, the lifetime of a statically attracting apparatus can be improved substantially.

Description

[Detailed Description of the Invention] [Summary] It has a laminated structure of a base plate, an elastic insulator, a pair of electrostatic adsorption electrodes, and a ceramic insulator, and the ceramic insulator is in direct contact with the substrate to be adsorbed. The surface strength is increased to prevent deterioration of adsorption ability due to leakage between electrostatic adsorption electrodes caused by flaws, and the elastic insulator absorbs thermal expansion stress to prevent stress breakdown of the ceramic insulator. Electrostatic adsorption device designed to extend its service life.

[Industrial application field]

The present invention is applicable to dry etching, chemical vapor deposition, spuck,
The present invention relates to improvements in electrostatic chuck devices used as substrate holding means in wafer processing of semiconductor devices such as electron beam exposure.

In in-line manufacturing equipment used for wafer processing of semiconductor devices such as LSIs, electrostatic chuck devices are often used as wafer holding means because they have only one holding mechanism.

In an electrostatic chucking device, the thermal conductivity between an electrode, etc. equipped with a cooling (heating) means to which the electrostatic chucking device is fixed, and a wafer that is suctioned and held on the electrostatic chucking device is increased. The ability to maintain a uniform and stable wafer temperature is also required as an important function.

[Conventional technology]

In order to increase the thermal conductivity between the wafer and the wafer, it is necessary to increase the contact efficiency between the adsorption surface of the electrostatic adsorption device and the wafer surface.

For this purpose, the following two types of structures have been used in conventional electrostatic chuck devices.

The first is a structure in which the DC voltage applied to the adsorption electrode is increased to increase the adsorption force, and this adsorption force allows the wafer to be tightly fixed on the top surface of the adsorption device while correcting warpage. For example, the main part is shown in Figure 3. As shown schematically in cross section, a pair of electrostatic adsorption electrodes 52A and 52B with a thickness of about 5 to 10 μm made of a vapor-deposited film or the like are adhered to a temporary ceramic base 51 having a thickness of about 101 m and having high thermal conductivity. A ceramic film 53 having a thickness of about 0.01 to 0.21 mm was deposited over the surface to which the electrode was deposited by sputtering.

The second method is to configure the upper surface of the electrostatic chuck device, that is, the wafer fixing surface, with an elastic insulating film such as a rubber material so that the top surface of the electrostatic chuck device is along the wafer surface. It has a structure that increases the contact area with the device, for example, as shown schematically in the cross section of the main part in FIG.
Thickness 0 made of comb material etc. on which thermal resistance reduction means are taken
．． A first elastic insulating film 55 of about 2 to 0.31 B is deposited, and a pair of electrostatic adsorption electrodes 56A, 56 made of copper or the like and having a thickness of about 20 μm are deposited on the first elastic insulating film 55.
B was adhesively disposed, and a second elastic insulating film 57 having a thickness of about 0.1 to 0.2111 mm and made of a rubber material similar to that described above was adhered onto the electrode disposing surface.

[Problem that the invention seeks to solve]

However, in the first conventional structure, the electrostatic adsorption electrode 5
The thin ceramic film 53 covering 2A and 52B is easily damaged and peeled off due to stress caused by thermal expansion, and it is difficult to manufacture because a thick film must be formed by vapor deposition, sputtering, etc., and the manufacturing cost is also very high. (There was a problem.

In addition, in the second conventional structure, since the contact surface with the wafer is composed of the second elastic insulating film 57 made of a thin rubber material, it is easily damaged by contact with the wafer, and minute pieces of the wafer etc. This causes a problem in that current leaks through the wafer between the adsorption electrodes 56A and 56B, resulting in deterioration of adsorption performance.

The problem to be solved by the present invention is that conventional electrostatic adsorption devices lack durability against thermal and mechanical shocks such as thermal expansion stress and wafer contact, as described above.

[Means for solving problems]

The above problem is caused by the base plate (1) made of a conductive material and the elastic insulating film (3) deposited on the entire surface of the base plate (1).
, film-like first and second electrodes (5A) (5B) attached to the elastic insulating crotch, and the first and second electrodes (5A).
) (5B) is deposited on the entire surface of the elastic insulating film (3) and constitutes the contact surface with the adsorbed substrate (11)! (6) and the first and second electrodes (
This problem is solved by the electrostatic adsorption device according to the present invention in which a DC voltage (9) is applied between 5A) and 5B.

[For production]

Accordingly, in the electrostatic adsorption device of the present invention, a ceramic thin plate is formed by adhering a pair of adsorption electrodes on the back surface of a metal base plate having high thermal conductivity through an elastic insulating film, and The ceramic thin plate and the metal base are bonded and bonded face to face, and the strong surface strength against friction, pressure welding, etc. of the ceramic thin plate prevents mechanical damage to the wafer adsorption surface, and the elasticity of the elastic insulating film prevents the ceramic thin plate and the metal base. It absorbs stress due to thermal expansion that occurs between the ceramic thin plate and the ceramic plate, thereby preventing thermal destruction of the ceramic thin plate, thereby improving durability.

〔Example〕 The present invention will be specifically explained below with reference to illustrated embodiments.

FIG. 1 is a side sectional view of an embodiment of the present invention, and FIG. 2 is a perspective plan view of an electrode pattern in an embodiment of the present invention.

Identical objects are designated by the same reference numerals throughout the plan.

As shown in FIGS. 1 and 2, the electrostatic chuck device according to the present invention is made of a metal having high heat and conductivity, such as aluminum, and has a through hole 2 in the center.
It is made of silicon rubber, fluorine rubber, etc., which has a filler such as silicon carbide or alumina mixed therein to increase thermal conductivity, on a flat disk-shaped metal base plate 1 of about o++m size, and has a hole in the center. A flat elastic insulating film 3 having a thickness of approximately 0.2 to 0.3*=a is coated with a rubber-based adhesive 4, for example.
It is adhesively fixed with
g) - Made of sintered alumina or the like with a thickness of about QJmm, on which a pair of electrostatic adsorption electrodes 5A and 5B of the shape shown in the figure made of Parasilane (Pd) film are deposited by vapor deposition or the like. A thin ceramic plate 6 having high thermal conductivity is adhesively fixed on the elastic insulating film 3 with, for example, a com-based adhesive 7, with the electrodes 5A and 5B disposed surfaces in contact with each other, and the electrodes 5A and 5B are Wires 8A and 8B connected to one end of
It has a structure in which it is connected to both ends of a DC power source 9 having a potential difference of about 2'KV, for example, through the through hole 2 and through means 17717 (not shown).

Note that FIG. 1 schematically shows the state in which the electrostatic adsorption device 10 is used in a dry etching device, and in the figure,
11 is a wafer to be processed, 12 is an etching electrode, 13 is a water cooling means, 14 is a fixed screw, 15 is a counter electrode, 16 is a high frequency power source, P is a plasma, and GND is a grounding portion.

According to the structure of the present invention, since the substrate adsorption/holding surface with which the wafer 11 to be processed comes into direct contact is constituted by a thin ceramic plate 6 made of sintered alumina or the like with an extremely high surface height, collision with the wafer 11 to be processed, It will not be damaged by friction or minute pieces of the wafer.

In addition, due to thermal expansion caused by the temperature rise of the substrate suction/holding surface, that is, the ceramic thin plate 6 during dry etching, the stress generated between the etching electrode 12, etc., which has a cooling means, and the metal base plate 1, which is in direct contact with the etching electrode 12, etc. Since the stress is absorbed by the elastic insulating film 3 interposed between the ceramic thin plate 6 and the metal base plate 1, the stress will not be applied to the ceramic thin plate 6 and cause the ceramic thin plate 6 to break. Therefore, the insulation between the electrostatic adsorption electrodes 5A, 5B and the wafer to be processed deteriorates, and the electrostatic adsorption electrode 5
This prevents the deterioration of the durability life caused by current leakage between A and 5B, which deteriorates the substrate adsorption function.

〔Effect of the invention〕

As described above, according to the present invention, the durable life of the electrostatic chuck device is improved, so the present invention is extremely effective for in-line semiconductor wafer processing when manufacturing LSIs and the like.

[Brief explanation of the drawing]

Fig. 1 is a schematic side sectional view of an embodiment of the present invention, Fig. 2 is a perspective plan view of an electrode pattern in an embodiment of the invention, and Fig. 3 is a sectional view of main parts of the first conventional structure. FIG. 4 is a sectional view of a main part of the second conventional structure. In the figure, ■ is a metal base plate, 2 is a through hole, 3 is an elastic insulating film, 4.7 is an adhesive, 5A and 5B are electrodes for electrostatic adsorption, 6 is a ceramic thin plate, 8A and 8B are wiring, 9 indicates a DC power supply. Spear 4 One picture-

Claims (1)

[Claims] A base plate (1) made of a conductor, and an elastic insulating film (1) coated on the entire surface of the base plate (1).
3), film-like first and second electrodes (5A) and (5B) deposited on the elastic insulating film, and an elastic material having the first and second electrodes (5A) and (5B). a ceramic film (6) that is deposited on the entire surface of the body insulating film (3) and forms a contact surface with the adsorbed substrate (11);
, an electrostatic adsorption device characterized in that a DC voltage (9) is applied between the second electrodes (5A) and (5B).